Herbert l



(No Model.) 7

H. L. ANDREWS, D. SGHUSTEK & T. H. COSTELLO.

DOVETAIL JOINT.

No. 419,133. Patented Jan. 7,1890.

UNITED STATES PATENT OFFICE.

HERBERT L. ANDREXVS, DANIEL SCIIUSTEK, AND THOMAS H. COSTELLO, OF CHICAGO, ILLINOIS, ASSIGNORS TO THE A. H. ANDRE\VS AND COMPANY, OF SAME PLACE.

DOVETAIL JOINT.

SPECIFICATION forming part of Letters Patent No. 419,133, dated January 7, 1890.

Application filed June 11, 1887. Serial No. 24:1,081. (No model.)

To all whom it may concern: the mortise until the two parts have been Be it known that we, HERBERT L. ANDREWS, brought nearly to their final position, when DANIEL SCHUSTEK,anClTHOMAS H. CosTELLo, they will fit tightly together, as illustrated in residing at Chicago, in the county of Cook the drawings, and hereinafter described.

andState of Illinois, andcitizens of the United That which we claim as new will be set States, have invented a new and useful Imforth in the claim.

provement in Dovetail Joints, of which the In the drawings, A represents a school-seat following is a specification, reference being arm provided on its upper side with a dovehad to the accompanying drawings, inwhichtail tenon a cast with the remaining portion 1 0 Figure 1 is a side elevation showing a schoolof the arm. This tenon is considerably higher seat arm with the wood thereon in section. at one end Z2 than at the other end 0, as shown Fig. 2 is a top view of a seat, some parts he in Figs. 1, 4, and 5. ing cut away to show the top of the tenon of d f are flanges on the arm A. the dovetail joint. Fig. 3 is a plan of the The upper surface of the tenon tapers grad- I 5 mortise in the wood. Fig. 4 is a section at ually and uniformly 011 a curved line from line w of Fig. 1. Fig. 5 is a section at line y one end to the other. The sides of the tenon of Fig. 1. taper gradually from the top to the bottom,

Our invention is primarily designed to be as usual, and also from one end to the other, used for uniting the wood and metal portions so that the bottom of the tenon is much nar- 20 of school and other seats and desks, but may rower at one end than at the other, as shown be used for other purposes. It is common to in Figs. at and 5. The mortise in the wood B, provide iron standards with dovetail tenons which is to be applied to the described tenon, to enter dovetail mortises in the wood parts corresponds in form to the tenon-that is to which form the seat, the back, and the top of say, the mortise is deeper at one end than at 2 5 school seats and desks. Heretofore such tenthe other. The throat of the mortise is narons and mortises have usually been made of rower at one end than at the other, and the uniform size from end to end, and as the two inclined sides of the mortise taper from tenon and mortise must fit each other it reone end to the other, all as shown in the quires considerable force to drive the wood drawings.

0 parts onto the tenon, which wood parts are In applying the wood to the iron the shal- 8o usually made of a number of strips glued to= low end of the mortise is applied to the deep gether, thus forming, practically,a single piece end of the tenon, and the wood can he slipped of considerable width. onto the tenon nearly the whole length thereof edge-keys have been used in connection easily and without any binding; but when 3 5 with a tenon having a tapering dovetail form forced to place the sides of the mortise will on one side. Tapering dovetail joints of varifit the sides of the tenon from end to end as ous forms are also old; but such we do not closely as when the tenon and mortise are claim, broadly. made in the usual way. At the same time The object of our invention is to so form the flanges d fwill come in close contact with 40 the dovetail tenon and mortise that a comthe wood on each side of the throat of the paratively wide board provided with suitable mortise, and this will aid in holding the two mortises can be applied to along tenon easily, parts securely together. The flanges will not and so that the parts will be held firmly tocome in contact with the wood until it has gether when in place without any additional been brought nearly to its final position. By

45 fastenings, which we accomplish by making using this form of tenon and mortise the apthe mortise deeper at one end than at the plication of wood to metal is greatly faciliother, and by making the throat of the mortat-ed, requiring but very little force to drive tise wider at one end than at the other, and the wood upon the metal. by making the tenon of corresponding form, The tenons are cast upon the metal parts,

50 but of such size that the tenon fits loosely in the patterns being of the proper form.

' The mortises in the wood parts can be made rapidly by means of a cutting-tool, such as is now used for cutting mortises of uniform depth and size from end to end, it only being necessary to arrange a form on which the end of the frame which carries the tool can travel, so that the depth of thecutting will gradually increase from one end to the other of the mortise. Thus the described mortise of the proper form can be cut in a curved piece of wood as well as in a straight fit loosely on the tenon until the two parts have been brought nearly to final position.

WVhatwe claim as new, and desire to secure by Letters Patent, is-

The herein -described dovetail joint, consisting of a long tenon which is deeper at one end than at the other, its upper surface being gradually deepened uniformly on a curved line from end to end, and its sides tapered gradually inward from top to bottom, and also tapered uniformly from end to end in such a manner that the bottom of the tenon is narrow at its deepened end and broad at its shallow end, and a long mortise having a form corresponding to said tenon and adapted to fit thereon loosely until the said parts are brought firmly together throughout their length, substantially as described.

HERBERT L. ANDREXVS. DANIEL SOHUSTEK. THOMAS H. COSTELLO. Witnesses:

HARRY T. JONES, ALBERT H. ADAMS. 

